The invention relates in general to vehicle chassis and in particular to a bogie for rail cars such as trolley cars, with a half bogie or cradle frame which is supported in the traverse by vertical pins and is horizontally tiltable and connected by tie bars, and wherein the wheels of each wheel axle are supported independently for each side and are propelled.
It is known that instead of mounting the wheels on rigid connecting axles which cause squeaking in a curve, the wheels are disposed on half axles which are each supported in half bogies, where they are propelled either individually or only on one side. In this case, the half-bogies are supported by vertical pins in the traverse, which pins protect the half-bogies against inclining sideways, however, providing them with the necessary horizontal swing. In addition the half-bogies are kept at distance on both sides of the pin by two tie bars (Journal: Eisenbahn-Technische Rundschau (26) dated Aug. 7, 1977, page 519 picture 8).
Difficulties arise with this construction when the wheels as is required generally are supported in the half-bogies and are intermediately supported by springs. There is easily the danger that the wheels, under the influence of cross-directed forces, at the level of the upper rail edge, are turned in the half-bogies into an inclined position and thereby change the wheel track resulting in a derailment danger. It has been tried to avoid this danger by a forced parallel alignment of the axle tree boxes with the aid of two guide levers, which are connected by a cross-shaft supported at the bogie-frame. It can be realized that these levers have to be heavy and based on the size of the effective forces if a satisfactory effect is to be obtained, which also requires a corresponding space, not to mention the undesirable increase in weight.